Study On Titanium Dioxide Nanotube Arrays Modified By Non-precious Metal Elements And Their Electrocatalystic Properties

Electrocatalytic hydrogen evolution（HER）and electrocatalytic nitrogen reduction（eNRR）,as the hot research directions in the field of electrocatalysis,have the characteristics of zero carbon emission,less fossil fuel consumption and high product purity compared with traditional industrial production.HER reaction relies on the catalytic electrode to reduce H⁺to hydrogen at a certain potential in the liquid phase system.At present,the research in related fields mainly depends on platinum（PT）and Pt based catalysts.Although Pt and Pt based catalysts have high her performance,their cost as precious metals remains high and their reserves are small,so it is difficult to realize industrial production.Therefore,looking for an efficient non precious metal catalyst is an effective means to reduce the cost;eNRR reaction has many different mechanisms,and the main common feature is that nitrogen molecules are selectively dsorbed at specific sites on the catalyst surface at room temperature,pressure and external potential,and gradually protonated,finally forming two ammonia molecules and falling off.At present,the research in the related fields of eNRR involved a variety of elements and compounds,but there is an order of magnitude gap between the ammonia production rate studied at present and the Hubble Bosch method used in traditional industrial production,which is mainly due to the stronger selective adsorption of H⁺under given conditions,making HER a serious side reaction;And the nitrogen-nitrogen triple bond is too stable,which makes it difficult to crack at room temperature and pressure.Therefore,looking for efficient catalysts is an urgent problem in the field of eNRR.In the present work,anatase titanium dioxide nanotube array prepared by anodic oxidation method was used as the catalyst substrate,and 2H Mo S₂was prepared on the surface of titanium dioxide nanotube array by magnetron sputtering.The sputtered2H Mo S₂was transformed into 1T Mo S₂by cyclic voltammetry,in order to obtain HER and eNRR catalysts with higher performance,lower cost and easy preparation.The main contents are as follows:Firstly,using highly ordered TiO₂ nanotube arrays as catalyst substrates,molybdenum disulfide was sputtered onto TiO₂nanotube arrays by magnetron sputtering,Ti/TNT/2H Mo S₂series catalysts were prepared,and their eNRR and HER properties and mechanisms were studied.According to the existing conclusions,among the Ti/TNT/2H Mo S₂series catalysts,20 V-Ti/TNT/2H Mo S₂-30min catalyst has the best eNRR performance,and its ammonia production rate can reach 11.140μg/（h?cm²）,the optimal Faraday efficiency reaches 31.46%at-0.1 V（vs.RHE）;30V2h-Ti/TNT/2H Mo S₂-30 min catalyst can make the current density on the catalyst surface reach 10 m A/cm²under the applied potential of-0.349 V（vs.RHE）.On this basis,Ti/TNT/1T Mo S₂series catalysts were prepared by crystal transformation of 2H Mo S₂by cyclic voltammetry,and the performance and mechanism of eNRR and HER were studied.Among them,20 V-Ti/TNT/1T Mo S2-30min catalyst has the best enrr performance,and its ammonia production rate can reach 16.151μg/（h?cm²）at-0.2 V（vs.RHE）,the optimal Faraday efficiency reaches29.86%at-0.1 V（vs.RHE）;20V-Ti/TNT/1T Mo S₂-30min catalyst can make the current density on the catalyst surface reach 10 m A/cm²under the applied potential of-0.347 V（vs.RHE）.